Dear OBB readers: Is this applicable to marriage?

From a OBB reader

I believe so much in this Chinese proverb: “No matter how far you have gone in the wrong direction, as soon as you know, turn back." Progress means getting nearer to the place you want to be. And if you have taken a wrong turning, then to go forward does not get you any nearer.

If you are on the wrong road, progress means doing an about-turn and walking back to the right road; and in that case the man who turns back soonest is the most progressive man. (Is this applicable to marriage? What do you do when you realize you have been with the wrong man or woman?)